Fitting a solenoid core to a pole piece structure



R. BERNIER F eb. 24, 1970 FITTING A SOLENOID CORE TO A POLE PIECE STRUCTURE Filed Oct. 12, 1967 2 Sheets-Sheet 1 X II II II I Feb. 24, 1970 R. BERNIER 3,497,845

" FITTING A SOLENOID CORE TO A POLE PIECE STRUCTURE Filed (kit. 12, 1967 I 2 Sheets-Sheet 2 a 1%.2 1 544 .&

United States Patent Int. Cl. from 7/08 US. Cl. 335-234 6 Claims ABSTRACT OF THE DISCLOSURE In the construction of a magnetic structure and, more particularly, for the fitting of a solenoid core to a pole piece, the core is provided with a groove which co-operates with a slot provided in the pole piece, in a direction at right angles to the core main dimension, said groove having two flanges and the pole piece being tightly held between the said flanges.

This invention relates to the construction of relays, arc-quenching electromagnetic devices used in circuitbreakers, electromagnetic or magnetic actuators and more generally, permanent magnet or electromagnetic structures of the lifting, holding or releasing types, including elongated flux-generating elements such as permanent magnets or solenoids having a ferromagnetic core and flux-carrying elements, such as yokes or pole pieces, forming with the flux-generating elements a magnetic circuit, said flux-carrying elements having plane portions substantially at right angles to the elongated flux-generating elements which are secured thereto.

One of the objects of this invention is to provide a magnetic structure construction in which the flux-generating and flux-carrying elements are fitted together in a simple and inexpensive way, the construction being, however, rugged and highly efiicient in action. Another object is to provide an assembly of a flux-generating and a flux-carrying element, in which the many and various disadvantages, deficiencies and defects of magnetic structure constructions heretofore known may be dependably and reliably overcome in a thoroughly practical way.

Another object is to provide an assembly of the abovementioned character, in which the flux-generating elements may be easily positioned or removed, even though the magnetic structure be comparatively complex and include a plurality of flux-generating elements.

Yet another object is to provide a magnetic structure of the above-mentioned character, in which the magnetic reluctance of the bond between the flux-carrying and flux-generating elements is substantially constant as a function of environment variations. Still another object is to provide an A-C relay structure capable of high sensitivity of action, in which the core sleeve around which the energizing coil is wound forms a magnetic gap between the core and the flux-carrying element.

These and other objects of the invention will become apparent from the following description.

In the accompanying drawings:

FIG. 1 is a perspective view of the core and stationary magnetic circuit of a relay constructed in accordance with the invention, of which FIG. 2 is a front elevation, and

FIG. 3 is a horizontal sectional view as seen along the line I-I of FIG. 2;

FIG. 4 is a front elevation of a modified magnetic structure, of which FIG. 5 is a sectional view as seen along the line H- II of FIG. 4, and

3,497,845 Patented Feb. 24, 1970 ice FIG. 6 is a sectional view taken along the line III- III in FIG. 4;

FIGS. 7 and 8 are partial sectional views of modified embodiments of the magnetic structures which are illustrated in FIGS. 1-6;

FIG. 9 is a front elevation of a bi-stable relay built in accordance with the invention, of which FIG. 10 is a sectional view as seen along the line IV- IV of FIG. 9, and

FIG. 11 is a sectional view as seen along the line V-- V of FIG. 9.

Referring to FIGS. l3 of the drawings, there is illustrated an L-shaped magnetic yoke l-la and an elongated core 2 secured to part 1a of the yoke, at right angles thereto. The core insulating sleeve 6 supports an energizing winding, not illustrated.

The yoke 1-1a will be for instance the stationary part of the magnetic circuit of a relay having a movable armature, not illustrated. The problem with which the present invention has to cope is the fitting of the flux-producing element 2 to the flux-carrying element 1a.

In accordance with this invention, on end of the elongated flux-producing element 2 is provided with a grooved portion 7 which is fitted by force into a slot 5. The slot 5 is cut out in the upper part of member 1a, so that the grooved portion 7 may be removed therefrom by pulling upwardly on the core. It is remarked that the core can not be removed from the magnetic circuit in the heretofore known constructions, as it should be pulled out in a direction parallel to the length thereof, which is not usually possible due to the conformation of the magnetic circuit, particularly the armature, against which the core would abut. A particular feature of this invention is that the core is fitted and removed in a direction substantially at right angles to the length thereof.

Another feature is that the fitting is more simple and inexpensive than the heretofore generally used screwed, riveted or adhesive joints, and better adapted to magnetic flux transfer with constant magnetic reluctance.

The easy removalof the core will enable one to fit difi'erent types of flux producing elements on one single type of yoke, which is highly advantageous in mass production of relays adapted for use with energizing currents of various voltages.

Referring again to FIGS. l-3, the grooved part 7 is bounded by two disc-shaped members 3 and 4 integrally built with the core. The members 3 and 4 will closely engage the surface of part 1a and improvxe the flux transfer from the core to the yoke.

Advantageously, the grooved part 7 is turned on lathe, after the core 2 has been pressed within the moulded sleeve 6.

In the modified embodiment which is illustrated in FIGS. 4-6, wherein the same reference numerals refer to similar parts as in FIGS. 1-3, the grooved part 7 is bonded by disc-shaped member 4 and by the end surface 3a of the core. In this embodiment, the core is manufactured separately and then lodged within the sleeve 6, to which it is attached by means of a clip 8.

In each of the modified embodiments which are illustrated in FIGS. 7 and 8, the terminal portion of the sleeve 6 forms first and second flanges 6a and 4a defining therebetween a grooved portion 7d which is fitted by force in the corresponding slot 5 (not illustrated) of part 1a.

A magnetic gap is provided, by sleeve 6, between the core 6 and part 1a. In FIG. 7, the said gap d is at right angles to part 1a, whereas in FIG. 8, the gap d is parallel to part 1a.

The embodiments of FIGS. 7 and 8 will be preferred when the magnetic structure is energized by alternating current: the gap will practically cancel the effect of remanent magnetism and therefore will avoid any adherence 3 v of the armature to the core after the current has been cut out.

This is very important in practice, as the sensitivity of the relay largely depends on it.

The bi-stable' relay which is illustrated in FIGS. 9-11 has two separate coils 13a, 13b wound on the same magnetic core 2, on which are fitted three pole pieces 11a, 11b, 110 which form the stationary part of the fluxcarrying magnetic circuit. The pole pieces cooperate with a movable armature 12 which pivots about pole piece 11b so as to engage either pole piece 11a or pole piece 11c. The construction of this well known type of relay involves important difliculties as far asthe fitting of the pole pieces to the core is concerned and, in the heretofore known constructions, the pole pieces, and, therefore, the coils, are not removable. In accordance with this invention, the core 2 is provided with grooved parts 7a, 7b, 70 which co-operate with slots, such as a, provided in the respective pole pieces. As apparent from FIG. 10, the slot 5a does not open on one side of the pole piece 11b, but includes an enlarged portion 9a through which the core will be easily introduced, before fitting by force the grooved part 7b thereof into the smaller section of the slot. Of course the two other slots, which respectively co-operate with the grooved parts 7a and 7c, are similar to slot 5a.

It is clear that positioning and removal of the pole pieces from the core will be easily performed with such a construction.

In case it is desired to manufacture a bi-stable polarized relay, the windings 13a and 13b will be suppressed and the core 2 will be substituted by a rod-shaped permanent magnet having for instance a South pole at both ends and a North pole in the middle part thereof. The pole pieces will be fitted on said permanent magnet in a way similar to that illustrated in FIG. 10. It is remarked that the problem of fitting a permanent magnet to a pole piece or other flux-carrying element is particularly difficult, as the magnetic properties of the permanent magnet material should not be modified by the fixing process and as the magnetic reluctance of the joint should not vary as a function of temperature or other environment conditions, which prevents from sticking the magnet to the pole piece.

As many possible embodiments may be made of the above invention and as many changes might be made in the embodiments above set forth, it is to be understood that all matter hereinbefore set forth, or shown in the acv companying drawings, is to be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In a magnetic structure of the character described, the assembly of at least one elongated flux-producing element with at least one-flux-carrying element, said flux-carrying element having a plane surface portion substantially at right angles to the main dimension of the flux-producing elements, wherein said flux-producing element has at least one groove having two shoulder forming flanges, which are substantially at right angles to the said main dimension and a reduced portion between said flanges, said plane surface portion having at least one slot in which the said reduced portion is fitted, said plane surface portion being tightly held between the two flanges.

2. An assembly as claimed in claim 1, said flux-carrying element being L-shaped and including a first plane surface portion substantially at right angles to the main dimension of the flux-producing element and a second plane surface portion substantially parallel to the said main dimension, wherein the said shoulder forming flanges consist of two disc-shaped members substantially at right angles to the said main dimension, said slot being provided in said first plane surface portion and having a main dimension which is substantially at right angles to said second plane surface portion, the said disc-shaped members closely engaging the first plane surface portion.

3. An assembly as claimed in claim 1, wherein the said reduced portion is annular, said slot having a restricted portion co-operating with said reduced portion and an enlarged portion adapted for engagement of the flux-producing element.

4. An assembly as claimed in claim 1, wherein the flux-producing element includes a central core having an end surface and an insulating sleeve around said core, said sleeve having a terminal portion which forms first and second flanges and said reduced portion between said flanges, said flanges closely engaging the said surface portion and a magnetic gap between the end surface of said core and the said surface portion.

5. An assembly as claimed in claim 4, wherein a further magnetic gap is provided between the end surface of said core and the said slot.

6. A structure as claimed in claim 1, said structure being a bi-stable relay having an elongated ferro-magnetic core provided with three grooves respectively at the ends and in the middle part thereof and three plane pole pieces each having a slot, each of the grooves having a pair of shoulder forming flanges which are substantially at right angles to the main dimension of the core and a reduced portion between the flanges of said pair, the respective reduced portions being closely fitted in the respective slots and the plane pole pieces being tightly held between the r respective pairs of flanges.

References Cited UNITED STATES PATENTS 1,016,567 2/1912 Kaisling 335 281 XR 1,467,973 9/1923 Hunt et a1 336-210 XR 2,395,164 2/1946 Cole 335-254 XR 3,106,669 10/1963 Zerwic 336- XR 3,314,032. 4/1967 Erden 33S281 XR G. HARRIS, Primary Examiner US. Cl. X.R. 

